Percutaneous myocardial revascularization device and method

ABSTRACT

Devices and methods for creating a series of percutaneous myocardial revascularization (PMR) channels in the heart. One method includes forming a pattern of channels in the myocardium leading from healthy tissue to hibernating tissue. Suitable channel patterns include lines and arrays. One method includes anchoring a radiopaque marker to a position in the ventricle wall, then using fluoroscopy repeatedly to guide positioning of a cutting tip in the formation of multiple channels. Another method uses radiopaque material injected into each channel formed, as a marker. Yet another method utilizes an anchorable, rotatable cutting probe for channel formation about an anchor member, where the cutting probe can vary in radial distance from the anchor. Still another method utilizes a multiple wire radio frequency burning probe, for formation of multiple channels simultaneously. Still another method utilizes liquid nitrogen to cause localized tissue death.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. Provisional PatentApplication No. 60/064,169, filed Nov. 4, 1997.

FIELD OF THE INVENTION

The present application is related to devices and methods for promotingblood circulation to the heart muscle. Specifically, the presentinvention is related to percutaneous myocardial revascularization (PMR)devices and methods for forming multiple channels in the myocardium.

BACKGROUND OF THE INVENTION

A number of techniques are available for treating cardiovascular diseasesuch as cardiovascular by-pass surgery, coronary angioplasty, laserangioplasty and atherectomy. These techniques are generally applied toby-pass or open lesions in coronary vessels to restore and increaseblood flow to the heart muscle. In some patients, the number of lesionsare so great, or the location so remote in the patient vasculature thatrestoring blood flow to the heart muscle is difficult. Percutaneousmyocardial revascularization (PMR) has been developed as an alternativeto these techniques which are directed at by-passing or removinglesions.

Heart muscle may be classified as healthy, hibernating and "dead". Deadtissue is not dead but is scarred, not contracting, and no longercapable of contracting even if it were supplied adequately with blood.Hibernating tissue is not contracting muscle tissue but is capable ofcontracting, should it be adequately re-supplied with blood. PMR isperformed by boring channels directly into the myocardium of the heart.

PMR was inspired in part by observations that reptilian hearts muscle issupplied primarily by blood perfusing directly from within heartchambers to the heart muscle. This contrasts with the human heart, whichis supplied by coronary vessels receiving blood from the aorta. Positiveresults have been demonstrated in some human patients receiving PMRtreatments. These results are believed to be caused in part by bloodflowing from within a heart chamber through patent channels formed byPMR to the myocardial tissue. Suitable PMR channels have been burned bylaser, cut by mechanical means, and burned by radio frequency currentdevices. Increased blood flow to the myocardium is also believed to becaused in part by the healing response to wound formation. Specifically,the formation of new blood vessels is believed to occur in response tothe newly created wound.

What remains to be provided are improved methods and devices forincreasing blood perfusion to the myocardial tissue. What remains to beprovided are methods and devices for increasing blood flow to myocardialtissue through controlled formation of channel patterns in themyocardium.

SUMMARY OF THE INVENTION

The present invention includes devices and methods for creation ofmultiple holes in the myocardium of a human heart for percutaneousmyocardial revascularization. A pattern of holes is optimally createdextending from healthy tissue to hibernating tissue, thereby increasingthe supply of blood to hibernating heart muscle tissue. Creating acontrolled pattern of channels rather than simply a plurality ofchannels of unknown location can be accomplished using various methodsand devices. Holes can be considered the space left after a volumetricremoval of material from the heart wall. Channels have a depth greaterthan their width and craters have a width greater than their depth.

One method includes marking a first location in the heart muscle wallwith a radiopaque marker, then positioning a radiopaque cutting tiprelative to the radiopaque marker using fluoroscopy and cutting channelsin the myocardium where appropriate. Suitable markers can be secured tothe endocardium mechanically with barbs or pigtails or injected into themyocardium. Suitable channel patterns include lines, arrays, andcircular clusters of channels.

Another method includes injecting radiopaque material into the newlyformed channels, thereby marking the positions of the channels alreadyformed. The radiopaque material should be held in place with polymericadhesives for the duration of the treatment. The channels formed can beviewed under fluoroscopy using this method. The marker can remainthroughout the procedure or only long enough to record the position formapping.

Yet another method can be accomplished by providing a myocardial channelforming device having an anchoring member, a treatment member with acutting tip, means for rotating the cutting member about the anchoringmember, and means for controlling the radial displacement of the cuttingtip from the anchoring member. The anchoring member can be implanted ina heart chamber wall using a pigtail, and the radial and rotationaldisplacement of the cutting tip controlled to sequentially form acircular cluster of channels about the anchoring member. The circularcluster preferably includes both healthy and hibernating tissue areas,which can be mapped using conventional techniques. A variant of thistechnique utilizes a device having a spline and corresponding starshaft, which restricts the number of possible rotational angles andprovide predictable arc rotations around the spline for the treatmentmember about the anchoring shaft.

Still another method utilizes a bundle of fibers within a sheath as thecutting device. Preferred fibers are formed of Nitinol wire and carryradio frequency current to effect burning channels in the myocardium.Optical fibers carrying laser light for burning are used in anotherembodiment. The splay of fibers out of the distal end of the sheath canbe controlled by controlling the bias of the fibers. The bias of thefibers can be controlled by utilizing shape memory materials, such asNitinol wire. The splay of fibers can also be controlled by controllingthe length of fiber exposed at the distal end, by controlling theretraction of the sheath over the fibers.

A variant device utilizes a magnetically responsive anchoring member,which can be pulled against the heart wall by an external magneticforce. The heart wall can have movement lessened during this procedureand other procedures generally, by inserting a catheter having amagnetically responsive distal region into a coronary artery. Force canbe brought to bear upon the heart wall region having the catheterdisposed within by applying a magnetic force on the catheter. Theapplied force can exert a pulling force on the catheter, reducingmovement of the beating heart wall in that region.

Another device includes an outer positioning tube having several sidechannels in the distal region and means for securing the distal regionagainst movement within the heart chamber. One securing means includes asuction orifice near the distal end supplied with vacuum by a vacuumlumen extending the length of the outer tube. Another securing meansincludes a magnetically responsive portion of the outer tube. Thesuction orifice can be secured to the heart chamber wall by applyingvacuum and the magnetically responsive portion can be forced into thechamber wall by applying an external magnet field. The inner tube cancontain an intermediate guide tube and the guide tube can contain aninner PMR cutting wire with a arcuate biased distal region. As thearcuate distal region is moved through the outer tube distal region andover the side channels, the PMR wire distal region can extend through aside channel and to the heart chamber wall. The PMR wire can be movedpast undesired side holes by rotating the wire such that the arcuatewire region is oriented away from the side holes.

Another device includes a tube-in-a-tube configuration, having an outertube disposed about an intermediate tube disposed about an inner PMRcutting probe. The inner PMR probe can be preformed to have a distalregion arcuate or angled bias, bent away from the longitudinal axis ofthe probe. The PMR probe distal region can extend through a side channelin the distal region of the intermediate tube and is slidable within theintermediate tube, thereby exposing a varying length of distal PMR probeoutside of the intermediate tube. The intermediate tube is slidablydisposed within the outer tube which has an elongate slot to allowpassage of the PMR probe therethrough. Thus, the radial extent or lengthof extending PMR probe can be varied by sliding the PMR probe within theintermediate and outer tubes, the longitudinal position of the PMR probecan be varied by sliding the intermediate tube within the outer tube,and the rotational position can be varied by rotating the outer tubefrom the proximal end. Varying the amount of a preformed, bent PMR probeextending from the intermediate tube can also change the longitudinalposition of the PMR probe distal end.

Another device includes an elongate rod having a distal region securedto an outer collar, such that the outer collar can be pushed and pulled.The outer collar is slidably disposed over an intermediate tube. Aninner PMR cutting probe is slidably disposed within the intermediatetube. The inner PMR probe and intermediate tube together have a distalregion arcuate or bent bias or preform, such that distally advancing theouter collar over the intermediate tube straightens out the intermediatetube and proximally retracting the outer collar allows the arcuate biasor bend to be exhibited in the distal region shape of PMR probe andintermediate tube. The preform can exist in the PMR probe, intermediatetube, or both. The device includes means for anchoring the device to theventricle wall. Circles or arcs of myocardial channels can be formed byrotating the outer tube, extending the inner PMR probe, and varying theamount of arc to form distal of the outer collar.

Yet another device includes an anchoring member and a positionablecryanoblative treatment tube. The treatment tube can be formed of metaland be either closed or open ended. In use, the device is anchoredwithin a heart chamber and a cryogenic substance such a liquid nitrogendelivered through the tube and to the tube distal end. The liquidnitrogen can cause localized tissue death, bringing about the desiredhealing response. Still another device includes a plurality of splayed,cryanoblative tubes within a sheath. The tubes can be supplied withliquid nitrogen, which can be delivered through the tube lumens to thetube distal ends so as to cause localized myocardial tissue death atmultiple sites substantially simultaneously.

In yet another embodiment, a catheter assembly is provided including aguide wire having a proximal end and a distal end. An expandable member,which may be a wire loop, is disposed at the distal end of the guidewire. The expandable member is moveable between a first position and asecond position. In the first position, the member is collapsed to movethrough a lumen of a guide catheter. In a second position, theexpandable member has a transverse diameter, with respect to the lengthof the guide wire, greater than the transverse diameter of the guidecatheter lumen. An elongate catheter having a proximal end and a distalend is disposed on the guide wire. A therapeutic device is connected tothe distal end of the catheter. The therapeutic device can be a needle,hypotube, electrode or abrasive burr to form holes or craters in themyocardium of the patient's heart.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary, side, cutaway view of a left ventricle havingan anchorable, positionable PMR device within;

FIG. 2 is a fragmentary, side view of the PMR device of FIG. 1, showinganchor and treatment members is phantom within a catheter shaft;

FIG. 3 is a top view of the PMR catheter and ventricle of FIG. 1,showing a transverse cross-sectional view of the PMR catheter and afragmentary cross-section and projection of the ventricle wall;

FIG. 4 is a fragmentary, perspective view of a multiple-tip PMRtreatment device according to the present invention;

FIG. 5 is an end view of the multiple-tip PMR treatment device of FIG.4;

FIG. 6 is a fragmentary, side, cutaway view of a left ventricle having amagnetically anchorable, positionable PMR device within;

FIG. 7 is cutaway, perspective view of a heart having a magneticallypositionable PMR cutting tip within the left ventricle wall;

FIG. 8 is a perspective view of a heart having a magnetic, heart wallstabilizing catheter disposed within the left coronary artery, shown inphantom;

FIG. 9 is a perspective view of a multiple channel positioning devicefor forming multiple myocardial channels in a ventricle wall, havingdistal anchoring means and containing a guide catheter containing a PMRcutting wire, both drawn in phantom;

FIG. 10 is a fragmentary, perspective view of a device related to thedevice of FIG. 9, illustrated without distal anchoring means, betterillustrating a shape member within the device;

FIG. 11 is a perspective view of a tube-in-a-tube positioning device forpositioning a PMR cutting probe, having an outer tube containing aninner tube containing a PMR cutting probe;

FIG. 12 is a fragmentary, perspective view of a section through the PMRprobe of FIG. 11, better illustrating the shape member;

FIG. 13 is a perspective view of an extendable collar device forpositioning a PMR probe, having a slidable collar over an intermediatetube over a PMR cutting probe;

FIG. 14 is a fragmentary, side, cutaway view of a left ventricle havingan anchorable, positionable cryanoblative PMR device within;

FIG. 15 is a fragmentary, perspective view of a multiple-tipcryanoblative PMR treatment device according to the present invention;

FIG. 16 is a perspective view of yet another embodiment of the device inaccordance with the present invention;

FIG. 17 is a view of the device of FIG. 16 in use;

FIG. 18 is an alternate embodiment of the device of FIG. 16;

FIG. 19 is an alternate embodiment of the device of FIG. 16; and

FIG. 20 is an alternate embodiment of the device of FIG. 16.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates an anchorable percutaneous myocardialrevascularization (PMR) treatment catheter 20 disposed within a leftventricle 34. PMR catheter 20 includes an inner star shaft 24 disposedwithin an outer catheter shaft 22, an anchoring shaft 26 disposed withinstar shaft 24, and a treatment shaft or probe 30 disposed withincatheter shaft 22. Catheter shaft 22 has been cut away proximally inFIG. 1, illustrating inner star shaft 24 within. Anchoring shaft 26 hasan anchor 28 disposed at the distal end. In a preferred embodiment,anchor 28 has a pigtail or corkscrew configuration, capable ofreversibly securing itself to the ventricular wall through rotation ofanchoring shaft 26. One embodiment anchor includes a distal barb,capable of securing itself to the ventricular wall through translationof anchoring shaft 26, not requiring shaft rotation for anchoring. Inanother embodiment, anchoring shaft 26 includes a vacuum lumentherethrough terminating in a distal orifice or suction tip (not shown).Treatment shaft 30 has a distal cutting tip 32, shown embedded within asection of a left ventricular wall 36. The term "cutting" as used hereinincludes penetrating and channel forming by other means.

Referring now to FIG. 2, PMR catheter 20 is illustrated in more detail.Anchor shaft 26, extending through outer catheter shaft 22, includes adistal radiopaque marker 38. Treatment shaft 30, extending throughcatheter tube 22, preferably includes an arcuate, distal region 33 and adistal radiopaque marker 40. Radiopaque markers 38 and 40 can aid indetermining the positions of the anchoring and treatment shafts underfluoroscopy. Suitable radiopaque materials are well known to thoseskilled in the art, including barium, bismuth, tungsten and platinum.Referring now to FIG. 3, PMR catheter 20 is illustrated in a top,cross-sectional view taken through the catheter. In a preferredembodiment, anchoring shaft 26 is contained within an anchor shaft lumen27. Anchor shaft lumen 27 is preferably slidably disposed within aninner shaft such as star shaft 24. Inner shaft 24 preferably has a starshape and is disposed within a star lumen 25 having internal splinescorresponding to the vertices of star shaft 24. Treatment shaft 30 ispreferably slidably disposed within a treatment shaft lumen 31 withinthe wall of PMR outer shaft 22. As illustrated, treatment shaft 30cutting end 32 has formed several channels 42 in the myocardium ofventricular wall 36.

The use of PMR device 20 may now be discussed, with reference to FIGS.1, 2 and 3. Several degrees of freedom of movement of cutting tip 32 arepossible with the present invention. Treatment shaft distal region 33 ispreferably biased to assume a more radially extended position whenunconstrained by lumen 31. Cutting tip 32 may be seen to have a radialdistance "R" from anchoring shaft 26, as indicated in FIG. 2. Holdingthe axial displacement of anchoring shaft 26 and treatment shaft 30fixed while distally, axially sliding catheter outer shaft 22 over bothshafts 26 and 30 causes more of treatment shaft distal region 33 to bedrawn into outer shaft 22, thereby decreasing the radial distance R ofcutting tip 32 from anchoring shaft 26. Thus, by proximally fixing thelongitudinal positions of anchoring shaft 26 and treatment shaft 30, andsliding outer shaft 26 over a range of motion, a series of channelsalong a line extending radially outward from anchoring shaft 26 can becreated. It will be recognized that, to the extent the inner ventricularwall does not match the arcuate shape of treatment shaft distal region33, it may be necessary to adjust the longitudinal displacement oftreatment shaft 30 within outer shaft 22 as well, to enable cutting tip32 to reach the endocardium.

In addition to cutting a series of channels radially outward fromanchoring shaft 26, cutting tip 32 can also describe an arc abouttreatment shaft lumen 31, best visualized with reference to FIG. 3. Byrotating treatment shaft 30 within lumen 31, cutting tip 32 can sweepthrough an arc, cutting a regular series of channels into themyocardium. By varying radial distance R and the rotation of treatmentshaft 30, a regular series of arcs of channels can be formed, with thearcs having increasing radial distance from outer shaft 22.

Outer shaft 22 can also be rotated relative to anchoring shaft 26,thereby enabling the cutting of a regular series of channels in a circleabout anchoring shaft 26. In a preferred embodiment, an intermediatestar shaft such as shaft 24 is disposed between anchoring shaft 26 andouter shaft 22. Star shaft 24 can serve to restrict the rotationalpositions possible for outer shaft 22 relative to inner, anchoring shaft26. Outer shaft 22 having internal splines, is not freely rotatableabout the vertices of start shaft 24. In order for outer shaft 22 andcarried treatment shaft 30, to be rotated about anchor shaft 26, starshaft 24 can be star shaped only is a limited distal region, and outershaft 22 only splined in a limited distal region. In a preferredembodiment, star shaft 24 and outer shaft 22, at a location proximal ofthe cross section of FIG. 3, have smooth outer and inner surfaces,respectively. The smooth surfaces allow star shaft 24 to be rotatedwithin outer shaft 22 when star shaft 24 has been retracted proximallyinto the smooth region. After rotation, star shaft 24 can be advanceddistally, sliding within a spline of outer shaft 22. The rotation ofouter shaft 22 can thus be restricted when desired and enabled whendesired. When enabled, rotation of shaft 22 can thus be restricted to adiscrete set of rotational angles. Another embodiment of the inventiondispenses with intermediate, start shaft 24, allowing outer shaft 22 torotate directly about inner, anchoring shaft 26. In this embodiment, therotation of outer shaft 22 about anchoring shaft 26 is not restricted toa set of discrete rotational angles.

Cutting tip 32 can form a substantially regular pattern of channels.Cutting tip 32 preferably is formed of a wire such as Nitinol or elgiloyor stainless steel, and is capable of delivering the radio frequencycurrent used for cutting channels in the myocardium. A suitable devicefor radio frequency cutting is described in co-pending U.S. patentapplication Ser. No. 08/810,830, filed Mar. 6, 1997, entitledRADIOFREQUENCY TRANSMYOCARDIAL REVASCULARIZATION APPARATUS AND METHOD.By restricting the movement of cutting tip 32 to movements relative toanchor tip 28, a more regular pattern of channels can be formed, evenwith limited fluoroscopic feedback, relative to the pattern formed by acutting tip operating independent of the anchoring tip.

Referring now to FIG. 4, a multi-fiber treatment probe 50 isillustrated. Treatment probe 50 includes a plurality of wires or opticalfibers 54, having distal cutting tips 56, and enclosed within a sheath52. FIG. 5 illustrates and end view of multi-fiber probe 50, showingdistal cutting tips 56 in the pattern they would have approaching themyocardium. Probe 50 allows a pattern of channels to be formed in themyocardium at the same time, not requiring repeated re-positioning of asingle cutting tip such as cutting tip 32 of FIG. 2. Wires 54 arepreferably formed of Nitinol wire. Use of a bundle of fibers includingmetal wires or optical fibers allows use of RF or laser cutting means,respectively. RF and laser cutting allows use of fibers relatively closetogether, as illustrated in FIG. 5. Mechanical cutting tips, such asthose using rotating cutting blades, can require more space betweencutting tips, not allowing the dense coverage of FIG. 5. In oneembodiment, the cutting tips have an outside diameter "D" and an averageinter-strand distance "I", as illustrated in FIG. 5, where I is about 2to 3 times the value of D. The pattern of cutting tips can be controlledby utilizing radially outwardly biased cutting tips, which splay outwardas illustrated in FIG. 4. The amount of splay is controlled in oneembodiment by allowing the enclosing sheath to retract, allowing thecutting tips to splay further outward. Sheath 52 can preventuncontrolled flopping of distal cutting tips 56, which can present aproblem when large inter-strand distances are required, as with somemechanical cutting tips. The coverage of the cutting tips in FIG. 5allows creation of a complete pattern of channels in the myocardiumwithout requiring repositioning of the cutting tips.

In use, probe 50 can be positioned near the ventricle wall region to berevascularized, and RF current delivered through distal cutting tips 56.The resulting myocardial channels can be formed substantially at thesame time, and a similar pattern delivered to an adjacent ventricularwall area soon thereafter.

In another embodiment of the invention, not requiring illustration, aradiopaque marker can be delivered and secured to a position in theventricular wall. Suitable radiopaque materials include barium, bismuth,tungsten and platinum. Markers believed suitable include metal markershaving barbs or pigtails to securely engage the ventricle wall. Othermarkers, such as radiopaque gels injected into the ventricular wall, aresuitable provided they stay in place for the length of the procedure.Such markers are preferably injected from within the ventricle utilizinga catheter. A preferred method utilizes the cutting tip to first plantor inject a marker, followed by the cutting of a series of channels inthe myocardium. By utilizing a radiopaque distal cutting tip and afixed, implanted radiopaque marker, the relative positions of the twocan be viewed fluoroscopically and adjusted fluoroscopically, therebyallowing formation of a controlled pattern of channels. The radiopaquemarker provides a reference point for forming a pattern of channels inthe myocardium.

In another embodiment of the invention, the cutting tip injectsradiopaque material in conjunction with the cutting of a channel. Inthis embodiment, as each channel is formed, a radiopaque marker is left,creating a pattern of radiopaque markers viewable fluoroscopically. Thepattern of channels formed in the myocardium are thus immediatelyviewable, giving feedback to the treating physician as to the progressand scope of the pattern of channels. Suitable materials for injectioninto the myocardium are preferably biodegradable or absorbable into thebody soon after the procedure, allowing the myocardial channels to beperfused with blood. A device suitable for cutting and injection ofmaterial is described in copending U.S. patent application Ser. No.08/812,425, filed Mar. 16, 1997, entitled TRANSMYOCARDIAL CATHETER ANDMETHOD, herein incorporated by reference.

Referring now to FIG. 6, left ventricle 34 having a magneticallyanchorable, positionable PMR device 86 device within is illustrated. PMRdevice 86 is similar in some respects to PMR device 20 illustrated inFIG. 1, with device 86 differing primarily at the distal end ofanchoring shaft 26. Anchoring shaft 26 has a magnetically responsiveportion 80 at the anchoring shaft distal end. "Magnetically responsive"as used herein refers to a material capable of being attracted orrepelled by a magnet. Magnetically responsive portion 80 can be used inconjunction with external magnets to position anchoring shaft 26 againstthe ventricle wall. External magnets such as magnet 84 can be disposedexternal to the body, positioned to direct the distal end of anchoringshaft 26 into the center of a target area in the heart. In oneembodiment, the external magnets are rare earth magnets. In anotherembodiment, the external magnets are superconducting magnets. In apreferred embodiment, several magnets 84 are used to direct anchoringshaft 26 into the heart wall.

In use, magnets 84 can be used in conjunction with axially movinganchoring shaft 26 to plant anchoring shaft 26 in the desired location.Pairs of magnets in all three dimensions may not be required as the goalis to pull the anchoring shaft against a ventricle wall, not necessarilyto suspend it in place using the magnets. The magnets, in conjunctionwith a radiopaque anchoring shaft tip and fluoroscopy, can be used toguide the anchoring shaft into position and maintain position duringtreatment. In the embodiment illustrated, an anchoring spike 82 lies atthe distal end of anchoring shaft 26. Anchoring spike 82, drawn largerin FIG. 6 than in the preferred embodiment, is used to stabilize theposition of the anchoring shaft distal end once the desired position hasbeen reached. Another embodiment terminates anchoring shaft 26 withoutany spike, rather ending with magnet 80. Still another embodimentterminates anchoring shaft 26 with an orifice, such as a suction tip, incommunication with a vacuum lumen within shaft 26, allowing anchoringshaft 26 to be held in place by applying vacuum to the vacuum lumen andorifice, thereby securing the distal tip of shaft 26 with vacuum pullingagainst the heart chamber wall.

Referring now to FIG. 7, a heart 35 having a PMR catheter 90 disposedwithin. PMR catheter 90 includes a shaft 92, illustrated extendingthrough the aorta and into left ventricle 34. A magnetically responsedistal portion 94 is located near a distal cutting tip 96 on PMRcatheter 90. As illustrated, cutting tip 96 has been guided into leftventricular wall 36 and has cut a channel in the wall. External magnets84 can be used to position cutting tip 96 into the desired position withthe aid of fluoroscopy. Distal portion 94 is preferably radiopaque, toaid in guiding cutting tip 96 into position. As PMR catheter shaft 92provides some degree of support to cutting tip 96, and as the primarygoal is to pull cutting tip 96 into the ventricular wall, pairs ofmagnets in all three dimensions may not be required. External magnets 84serve to position cutting tip 96, and, with the assistance of cathetershaft 92, can serve to pull cutting tip 96 into the ventricular wall.

Referring now to FIG. 8, a magnetically responsive catheter 100 isillustrated, disposed within heart 35, being extended through aorta 102into a left coronary artery 104. Catheter 100 includes a magneticallyresponsive distal region 106, which can be attracted by external magnets84. Catheter 100 can be used in conjunction with external magnets tostabilize regions of the heart, lessening the amount of wall movementdue to the beat of the heart.

In use, magnetically responsive catheter 100 can be advanced with aid offluoroscopy through the aorta and into a coronary artery. Catheterdistal region 106 preferably includes radiopaque materials to aidpositioning under fluoroscopy. Once in position, distal region 106 iseffectively located in the heart wall. When stabilization is desired,external magnets such as magnet 84 can be positioned near catheterdistal region 106. By exerting a strong pull on distal region 106, themovement of the heart wall in the vicinity of catheter distal region 106can be lessened.

Stabilization can be used during intravascular PMR procedures, minimallyinvasive PMR procedures, and heart procedures generally. When usedduring PMR procedures, the stabilization can serve to lessen heart wallmovement in the area being cut. When used during other medicalprocedures, the stabilization can serve to minimize heart wall movementin areas being operated on or otherwise treated. When used duringintravascular PMR procedures, a second, PMR catheter should be provided.

Referring now to FIG. 9, a multiple-channeled PMR positioning device orguiding tube 120 is illustrated. Positioning tube 120 includes a distalend 122, a distal region 124, a proximal end 126, a plurality ofchannels 138 within distal region 124, and a lumen 128 therethrough. Adistal anchoring means 130 is preferably located distal of distal region124 and can serve to fix the position of distal end 122 to the wall ofthe left ventricle or other heart chamber. In one embodiment, anchoringmeans 130 includes an orifice or suction tip in communication with avacuum lumen 148, such that anchoring means 130 can be held in placeagainst a heart chamber wall once positioned near the wall. In anotherembodiment, anchoring means 130 includes a magnetically responsivematerial such that an externally applied magnetic field can forceanchoring means 130 into a heart chamber wall. In this magneticallyresponsive embodiment, anchoring means 130 can be similar to distalportion 94 illustrated in FIG. 7. In another embodiment, tube distalregion 124 is magnetically responsive and can be similar to magneticallyresponsive region 106 illustrated in FIG. 8. Distal tip 122 ispreferably formed of soft, atraumatic material and distal region 124formed of sufficiently pliable material so as to allow distal region 124to conform to a ventricle wall.

Disposed within positioning tube 120 is a guide catheter 142 extendingfrom positioning tube proximal end 126 to distal region 124. Disposedwithin guide catheter 142 is a PMR cutting wire 132, proximallyelectrically connected to an RF energy source 136 and terminatingdistally in a cutting tip 33. PMR wire 132 includes a distal arcuate orbent region 144 proximate distal cutting tip 33. Arcuate region 144 canbe bent or arced so as to have a preformed shape or bias to extendlaterally away from the longitudinal axis of the PMR wire. In oneembodiment, PMR wire lies within positioning tube 120 directly, withouta guide catheter. In a preferred embodiment, a guide catheter such asguide catheter 142 is disposed about the PMR wire. PMR wire 132 isslidably disposed within guide catheter 142 and can be rotated byapplying torque to the proximal end.

In use, positioning tube 120 can be preloaded with guide catheter 142containing PMR wire 132. PMR wire 132 can be retracted such that arcuateregion 144 is retracted either to a position proximal of channels 138 orwithin positioning tube distal region 124 but retracted within guidecatheter 142. In this retracted position, PMR wire arcuate region 144does not extent from channels 138. With PMR wire retracted, positioningtube 120 can be advanced through the vasculature into a heart chambersuch as the left ventricle. Positioning tube distal end 122 can beadvanced down into the ventricle and up a ventricular wall. With distalend 122 in a desired position, anchoring means 130 can be used to anchordistal end 122 to the ventricular wall. In embodiments where anchoringmeans 130 is magnetically responsive or where positioning tube distalregion 124 is magnetically responsive, an external magnetic force can beapplied to pull or push anchoring means 130 and distal region 124 intothe wall. In embodiments where anchoring means 130 is a suction tip,vacuum can be applied to the vacuum lumen in communication with thesuction tip.

With positioning tube distal region 124 in place, guide catheter 142containing PMR wire 132 can be advanced to push tube distal end 122 andPMR wire arcuate region 144 distally out of guide catheter 142. PMR wire132 can be rotated such that cutting tip 33 is oriented toward channels138, and guide catheter 142 and PMR wire 132 retracted together untilcutting tip 33 can be pushed out of channel 138. Cutting tip 33 can beadvanced through channel 138 and a channel cut into the myocardium. In apreferred embodiment, PMR wire 132 has a depth stop 146 proximal ofarcuate region 144 that limits the length of wire passed throughchannels 138, such that the depth of a PMR formed myocardial channel islimited. After myocardial channel formation, PMR wire 132 can beretracted through the channel and the next, more proximal channelentered. In a preferred embodiment, arcuate region 144 is radiopaque anda series of radiopaque marker bands separate channels 138 to aid inpositioning cutting tip 33. In one embodiment, PMR wire 132 can berotated to cut more than one myocardial channel per positioning tubechannel. In this manner, a series of myocardial channels in a regularpattern can be formed over the length of positioning tube distal region124.

Referring now to FIG. 10, another embodiment positioning tube 160 isillustrated. Positioning tube 160 has a shape member 164 which canassist in forming the U-shape of tube 160 illustrated in FIG. 10. In oneembodiment, shape member 164 is formed of a shape memory material suchas Nitinol and embedded within the wall of tube 160 to impart a shape tothe tube once tube 160 is within a ventricle and is no longer asrestrained as when disposed within a blood vessel or guide catheter. Inanother embodiment, shape member 164 is a pull wire slidably disposedwithin a lumen within tube 160 and fixedly attached to a distal portionof the tube as indicated at 166. In this embodiment, shape member 164can be pushed and pulled from a proximal location outside of thepatient's body so as to assist in imparting a shape to tube distalregion 124. In FIG. 10, the distal most portion of tube 160, includinganchoring means 130, has been omitted from the drawing to more clearlyillustrate the distal termination of shape member 164. From inspectionof FIG. 10, it may be seen that, by rotating positioning tube 160 todifferent anchoring positions, and by advancing PMR wire 132 to varioustube channels, a large expanse of ventricular wall can be covered andhave myocardial channels formed therein.

Referring now to FIG. 11, a tube-in-a-tube embodiment positioning device180 is illustrated. Positioning device 180 includes an inner PMR cuttingprobe 182 slidably disposed within an intermediate tube 184 which isslidably disposed within an outer tube 186. PMR probe 182 has a cuttingtip 188 and preferably has radiopaque marker bands 190. Marker bands 190aid in positioning the PMR probe under fluoroscopy. PMR probe 182 ispreferably preformed to have an arcuate or bent distal region 192.

Intermediate tube 184 has a channel 194 formed through the tube wallsufficiently large to allow passage of PMR probe 182. In a preferredembodiment, channel 194 is formed in a side tube wall in a distalportion of intermediate tube 184, as illustrated in FIG. 11. Outer tube186 has an anchoring tip 200 and a slot 196, with slot 196 illustratedextending along the longitudinal axis of the outer tube. Slot 196 issufficiently wide to allow passage of PMR probe 182 therethrough. In oneembodiment, anchoring tip 200 is formed of a soft material and held inplace by axial force directed along the longitudinal axis of device 180.In another embodiment, anchoring tip 200 contains a magneticallyresponsive material and is held in place at least partially byexternally applied magnetic forces. Referring now to FIG. 12, a sectionof PMR probe 182 is further illustrated, showing one structure forimparting a preformed arc or bend to the probe. PMR probe 182 caninclude a tube wall 199 having a preform wire 198 embedded therein.Preform wire 198 is preferably formed of a shape memory material such asNitinol, such that the arcuate or bent shape is reformed upon exit fromthe constraint of intermediate tube 184.

Referring again to FIG. 11, the wide range of motion possible forcutting tip 188 may be discussed. The radial extent of cutting tip 188,the distance from the center longitudinal axis of outer tube 186, can bevaried by extending PMR probe 182, thereby forcing a longer extent ofexposed probe through intermediate tube channel 194 and through outertube slot 196. As PMR probe 182 has arcuate region 192 in a preferredembodiment, extending PMR probe also changes the longitudinal positionof the cutting tip as more arc is exposed. Sliding intermediate tube 184within outer tube 186 also changes the longitudinal position of cuttingtip 188. Cutting tip 188 is illustrated at a first position A in FIG.11, a second, more distal position B, and a third, still more distalposition C, as intermediate tube 184 is advanced distally within outertube 186. Finally, outer tube 186 can be rotated about its center,longitudinal axis, thereby extending the range of coverage of cuttingtip 188.

In use, PMR positioning device 180 can be advanced into the leftventricle and anchoring tip 200 forced against some portion of thevermicular wall. Intermediate tube 184 can be slid within outer tube 186to a desired position. Inner PMR probe 182 can be advanced out ofchannel 194 until the desired length of PMR probe is exposed. A desiredposition of cutting tip 188 can be reached by adjusting the length ofPMR probe 182 exposed, the length of intermediate tube 184 advanced intoouter tube 186, and the rotation of outer tube 186. In one method, aseries of arcs of myocardial channels are formed substantiallytransverse to the longitudinal axis of positioning device 180. In thismethod, outer tube 186 is rotated such that cutting tip 188 describes anarc. As each arc is completed, intermediate tube 184 is slid relative toouter tube 186 and a new arc of channels is burned into the ventricularwall.

Referring now to FIG. 13, an extendable collar embodiment PMRpositioning device 220 is illustrated. Device 220 includes inner PMRprobe 182 disposed within an intermediate tube or sleeve 222 which isslidably disposed within an outer collar 224. Intermediate sleeve 222includes a distal end 240 and has a lumen 242 extending therethrough.Inner PMR probe 182 is preferably slidable within intermediate sleeve222. Device 220 includes an elongate rod 226 having a distal region 228secured to outer collar 224. In a one embodiment, elongate rod 226 iscapable of both pulling and pushing outer collar 224 over intermediatesleeve 222. An elongate anchoring member 230 includes a proximal region236, a distal end 234, a distal anchoring means such as pigtail 234, andcan be slidably and rotatably secured to outer collar 224.

In one embodiment, elongate rod 226 and anchoring member 230 are bothslidably disposed in a dual lumen tube 227 substantially coextensivewith intermediate tube 222. Dual lumen tube 227 can terminate the lumencontaining elongate rod 226 in a skived portion 229, continuing the tubeas a single lumen portion 231. Single lumen portion 231 allows elongaterod 226 to freely travel with outer collar 224. Outer collar 224preferably is slidably disposed over single lumen portion 231.

Intermediate sleeve 238 and inner PMR probe 182 together have an arcuateor bent bias or preform, as illustrated at 238. In one embodiment,intermediate sleeve 222 has a preformed shape which can be imparted withan embedded shape wire as illustrated by wire 189 in FIG. 12. In anotherembodiment, PMR probe 182 has an arcuate bias sufficiently strong toimpart a distal bend to both intermediate sleeve 238 and PMR probe 182when outer collar 224 is retracted. PMR probe 182 can include Nitinol orother shape memory material to impart this arcuate bias. In yet anotherembodiment, both inner PMR probe and intermediate sleeve 238 have apreformed arcuate or bent distal shape.

In one embodiment, intermediate tube 222 can be rotated within outercollar 224. In another embodiment, intermediate tube is restricted inrotation corresponding ridges and grooves between outer collar 224 andintermediate tube 222. In one embodiment, outer collar has internalridges fitting within external grooves in a region of intermediate tube222. Restricting the rotation of intermediate tube 222 within collar 224can aid in causing rotation about anchoring member 230 rather than aboutthe center of outer collar 224.

In use, outer collar 224 can be extended distally over intermediatesleeve 222, such that collar 224 is proximate intermediate sleeve distalend 240. Inner PMR probe 182 can be preloaded within intermediate sleeve222. With outer collar 224 distally extended, arcuate region 238 issubstantially restrained and straightened. Device 220 can be advancedwithin the vasculature and into a heart chamber such as the leftventricle. Elongate anchoring member 230 can be advanced distally androtated, thereby rotating pigtail 232 into the ventricle wall andsecuring anchoring member 230. With intermediate sleeve 222 and PMRcutting tip 188 positioned as indicated at "E" in FIG. 13, the extent ofPMR probe exposed can be adjusted by axially sliding PMR probe 182within intermediate sleeve 222. The extent of intermediate sleeveextending distally beyond collar 224 can be adjusted in some embodimentsby advancing or retracting sleeve 222 within collar 224. With PMRcutting tip 188 in position, intermediate sleeve 222 can be rotatedabout anchor member 230 and a circular pattern of myocardial channelscan be burned about the pigtail. In a variant method, possible indevices allowing rotation of intermediate sleeve 222 within outer collar224, intermediate sleeve 222 can be rotated about the center axis ofouter collar 224. With one circle completed, outer collar 224 can beretracted, allowing more of the preformed shape of sleeve 22 and PMRprobe 182 to appear, as illustrated, for example, at "D" in FIG. 13. Ascollar 224 is retracted, PMR probe 182 can be advanced to describecircular paths of increasing radius over the inner ventricle walls. Inthis way, a series of circular paths of myocardial channels about theanchoring point can be formed in the ventricle walls. In one embodiment,elongate member 226 is capable of only retracting collar 224, which,once retracted within the ventricle, cannot be advanced within theventricle. In another embodiment, elongate member 226 is capable of bothadvancing and retracting collar 224 over intermediate sleeve 222. Withthe formation of myocardial channels complete, anchoring member 226 canbe rotated opposite the initial rotation, thereby releasing pigtail 232from the ventricle wall.

FIG. 14 illustrates an anchorable, cryanoblative PMR treatment catheter320 disposed within a left ventricle 34. The term "cryanoblative", asused herein, refers to the delivery of cold sufficient to cause tissuedeath. Similarly numbered elements are discussed with respect to FIG. 1.Cryanoblative catheter 320 includes an inner star shaft 24 disposedwithin an outer catheter shaft 22, an anchoring shaft 26 disposed withinstar shaft 24, and a cryanoblative treatment tube 330 disposed withincatheter shaft 22. Cryanoblative treatment tube 330 is preferably formedof metal and can include a distal cryanoblative tip 332 and a lumenthrough which a cold substance, such as liquid nitrogen, is delivered.

In one embodiment, distal cryanoblative tip 332 includes a distalorifice in communication with the treatment shaft lumen, such thatliquid nitrogen can be delivered through the orifice and to the heartchamber wall. In another embodiment, tube 330 is close ended andinitially under vacuum, allowing liquid nitrogen to be delivered to thetube distal region, causing the tube to become very cold withoutallowing liquid nitrogen to enter the myocardium. The cryanoblative tipcan be inserted into the heart chamber wall, penetrating the wall, andinto the myocardium prior to delivery of liquid nitrogen. The deliveryof liquid nitrogen to the heart chamber wall can cause localized tissuedeath, bringing about the same healing response as laser andradio-frequency current PMR.

Referring now to FIG. 15, a multi-tube, cryanoblative treatment probe350 is illustrated. Treatment probe 350 includes a plurality ofcryanoblative tubes 354, having distal cryanoblative cutting tips 356,and enclosed within a sheath 52. In one embodiment, tubes 354 are feedfrom a common supply within sheath 52, such that tubes 354 have a shortlength, with most of the length lying distal of the sheath. Probe 350allows a pattern of channels to be formed in the myocardium at the sametime, not requiring repeated repositioning positioning of a singlecutting tip such as cutting tip 332 of FIG. 14. The pattern of cuttingtips can be controlled by utilizing radially outwardly biased cuttingtips, which splay outward as illustrated in FIG. 15. The amount of splayis controlled in one embodiment by allowing the enclosing sheath toretract, allowing the cutting tips to splay further outward. Sheath 52can prevent uncontrolled flopping of distal cutting tips 356, which canpresent a problem when large inter-strand distances are required, aswith some mechanical cutting tips.

The coverage of the cutting tips in FIG. 15 allows creation of acomplete pattern of channels in the myocardium without requiringrepositioning of the cutting tips. The resulting myocardial channels canbe formed substantially at the same time, and a similar patterndelivered to an adjacent ventricular wall area soon thereafter. Asdiscussed with respect to FIG. 14, cryanoblative tubes 354 can be formedof metal and be either closed or open ended.

In a variation of the methods previously described, a radiopaquecontrast media is used to determine the depth of channels formed in themyocardium. The contrast medium is injected or "puffed" into or near thechannel formed in the myocardium. The heart can be visualized underfluoroscopy to determine the depth of the channel formed thus far. Aftervisualization, the channel can be further deepened. The cycle of channelformation, contrast medium puffing, and fluoroscopic visualization canbe repeated until the channel has the desired depth.

Contrast medium could be injected using a lumen such as the lumen ofguide catheter 142 of FIG. 9. A lumen such as the lumen in tube 330 ofFIG. 14 could also be used to deliver contrast medium. The lumenspreviously discussed with respect to injecting liquid nitrogen could beused to deliver contrast medium.

In addition to using the device as described herein above to formchannels in the myocardium, the device could be used to form craters inthe myocardium. That is, to form a wound in the myocardium having awidth greater than its depth. The crater can be formed by controllingthe depth of insertion of, for example, a radiofrequency device and/orcontrolling the power delivered to the distal tip of the device suchthat a crater is formed. Those skilled in the art can also appreciatethat mechanical devices, laser devices or the like could be used to formcraters.

In use, the above methods and devices can be used to form a pattern ofchannels leading from healthy myocardial tissue to hibernating tissue.This can operate by multiple mechanisms to supply hibernating tissuewith an increased blood supply. First, channels in the myocardium canperfuse tissue directly from the ventricle, through the patent channelformed by the cutting tip. Second, the channels formed by the cuttingtip can become newly vascularized by operation of a healing response tothe channel injury. The new blood vessels thereby increase further thesupply of hibernating tissue by ventricular blood. Third, the series ofnewly formed vessels caused by the healing response can forminterconnections or anastomoses between the series of injured areas,forming a network of blood vessels, which, by connecting with healthyarea vessels, can be supplied by blood originating from coronaryarteries in addition to blood supplied directly by the ventricle.

FIG. 16 shows yet another embodiment of the present invention in theform of catheter assembly 400. Here only the distal end of catheterassembly 400 is shown disposed within the left ventricle of a patient'sheart. Those skilled in the art will appreciate the variousconfigurations possible for the proximal end of the catheter in view ofthe description of the distal end which follows. Catheter assembly 400includes an elongate guide wire 402 having a distal end and a proximalend. A collapsible loop 404 is hingably connected to the distal end ofguide wire 402. A retraction member 406 is hingably connected to loop404 opposite the connection to guide wire 402. Therapeutic catheter 408,which has a lumen extending therethrough, is shown advanced over guidewire 402. Catheter 408 has a distal end and a proximal end, andproximate the distal end of catheter 408 is a therapeutic member 410.Therapeutic member 410 can be an elongate electrode having a ball tip.In a preferred embodiment, a conductor extends through catheter 408 todeliver RF energy to electrode 410. Electrode 410 can be hingablyconnected to catheter 408 such that catheter assembly 400 can beadvanced through a guide catheter 412.

The materials to be used, and the methods of fabrication, to makecatheter assembly 400 will be known to one skilled in the art in view ofthe uses to which catheter assembly 400 are put. As shown in FIG. 16,loop 404 is disposed in a first collapsed position A. In collapsedposition A, loop 404 is advancable to left ventricle 34 of heart 35 by apercutaneous route through the aorta. FIG. 17 shows loop 404 in a secondposition B deployed within left ventricle 34. When loop 404 is in secondposition B, a portion of guide wire 402 lies near and approximatelyparallel to left ventricle wall 36, while a portion of loop 404 abutsthe opposite wall. In this position, catheter 408 can be advanced asshown by the arrow along guide wire 402. As catheter 408 is advanced,electrode 410 can be energized repeatedly to form holes or channels 442in wall 36. A further series of holes 442 can be formed by rotating wire402 and loop 404 as shown by the arrows adjacent loop 404.

In order to move loop 404 between first position A and second positionB, guide wire 402 should be relatively rigid in comparison to loop 404and actuator member 406. With that configuration, actuator 406 can bepulled proximately to move loop 404 from second position B to firstposition A. In turn, actuator member 406 can be moved distally to deployloop 404.

FIG. 18 is a view of the distal end of catheter 408 showing an alternatetherapeutic device. In particular, a hypodermic needle 414 is shownextending from distal end 408. Hypodermic needle 414 is preferablyhingable connected to catheter 408 such that it can be advanced andwithdrawn through a guide catheter. If catheter 408 includes an infusionlumen, contrast media, growth factor or other drug can be delivered towall 36 through needle 414.

FIG. 19 is a view of the distal end of catheter 408 showing yet anothertherapeutic device disposed thereon. In particular, an electrode 416 isshown which has a length greater than the distance which it extendstransversely from catheter 408. Such an electrode can be used to form acrater 444 having a width greater than its depth.

FIG. 20 is a view of the distal end of catheter 408 showing anothertherapeutic device disclosed thereon. In FIG. 20 an abrasive burr 418 isshown extending transversely from catheter 408. When rotated, burr 14can form a crater 444. In both FIGS. 19 and 20, electrode 416 and burr418 are shown spaced from heart wall 36. While creating craters 444, itis understood that loop 404 will be deployed in second position B suchthat electrode 416 and burr 418 will be in contact with heart wall 36.

It can be appreciated that each of the devices disclosed herein can bebi-polar as well as mono-polar. To make a bi-polar configuration, aground electrode would need to be disposed on the device proximate theelectrode(s) shown.

Numerous characteristics and advantages of the invention covered by thisdocument have been set forth in the foregoing description. It will beunderstood, however, that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of parts without exceeding the scope of theinvention. The inventions's scope is, of course, defined in the languagein which the appended claims are expressed.

What is claimed is:
 1. A device for creating a plurality of myocardialchannels comprising:an elongate tube having a distal port; an anchoringmember slidably disposed within said elongate tube, said anchoringmember having a pointed distal end extending from said elongate tubedistal port, said pointed distal end adapted to penetrate into saidmyocardium; a treatment member slidably disposed within said elongatetube, said treatment member having an arcuate distal region having acutting tip thereon, said arcuate distal region being biased to increasein radius when not constrained within said tube, such that said distallyextending said elongate tube causes said treatment member distal end todecrease in radial distance from said anchor member and proximallyretracting said elongate tube causes said treatment member distal end toincrease in radial distance from said anchor member.
 2. A device forcreating a plurality of myocardial channels as recited in claim 1,wherein said treatment member is disposed within a treatment memberlumen in said elongate tube distinct from said anchoring member lumen,such that said treatment member can be rotated about said anchoringmember by rotating said elongate tube about said anchoring member.
 3. Adevice for creating a plurality of myocardial channels as recited inclaim 2, further comprising means for restricting said rotation of saidtreatment member relative to said anchoring member to a finite set ofrotational positions.
 4. A method for increasing blood availability toheart muscle by causing localized tissue death at a plurality of sitesin the myocardium comprising the steps:providing a myocardial localizedtissue killing device having an anchoring member, at least one treatmentmember, and means for rotating said treatment member about saidanchoring member, wherein said treatment member includes means forkilling tissue in said myocardium; attaching said anchoring member to afirst position in said myocardium; rotating said treatment member to adesired rotational angle relative to said anchor; causing tissue deathin said myocardium; and wherein said treatment member includes a tubehaving a lumen therethrough and said causing step includes delivering acold substance through said lumen.
 5. A method as recited in claim 4,wherein said cold substance is liquid nitrogen.
 6. A method as recitedin claim 4, wherein said cold treatment member has a distal orifice influid communication with said treatment member lumen.
 7. A device forkilling tissue at a plurality of myocardial sites comprising:an elongatetube having a distal port; an anchoring member slidably disposed withinsaid elongate tube, said anchoring member having a pointed distal endextending from said elongate tube distal port, said pointed distal endadapted to penetrate into said myocardium; a treatment member capable ofcausing localized tissue death slidably disposed within said elongatetube, said treatment member having an arcuate distal region having atreatment tip thereon, said arcuate distal region being biased toincrease in radius when not constrained within said tube, such that saiddistally extending said elongate tube causes said treatment memberdistal end to decrease in radial distance from said anchor member andproximally retracting said elongate tube causes said treatment memberdistal end to increase in radial distance from said anchor member,wherein said treatment member is disposed within a treatment memberlumen in said elongate tube distinct from said anchoring member lumen,such that said treatment member can be rotated about said anchoringmember by rotating said elongate tube about said anchoring member.
 8. Adevice as recited in claim 7, wherein said treatment member includes alumen adapted to deliver liquid nitrogen to said treatment member distalend.
 9. A device as recited in claim 8, wherein said treatment memberdistal end includes an orifice in communication with said treatmentmember lumen.